# A003120 (b-file synthesized from sequence entry) 1 1 2 1 3 2 4 3 5 7 6 13 7 31 8 66 9 159 10 365 11 900 12 2162 13 5417 14 13436 15 34165 16 86603 17 223028 18 574493 19 1495524 20 3900055 21 10246172 22 26982966 23 71447432 24 189664782 25 505605729 26 1351179886 27 3623051567 28 9737403960 29 26243202664 30 70878565004